At the present time, physicians often treat carotid artery obstructive disease with the placement of a stent. This stent is typically placed in the internal carotid artery, in the common carotid artery, or spanning both arteries with the distal portion of the stent in the internal carotid artery and the proximal portion of the stent in the distal common carotid artery. The start of this procedure necessitates the placement of either a long sheath or a guiding catheter into the common carotid artery proximal to the carotid stenosis to be treated. The placement of such a sheath or guiding catheter can often be extremely challenging due to the tortuous course for access from the aortic arch into the common carotid artery. This is particularly an issue when accessing the right common carotid artery, which typically arises as a proximal branch from the inominate artery. Many different “tricks” are used to try to place relatively stiff sheaths and guiding catheters into the carotid circulation. One such “trick” is to have the sheath track over a “super-stiff” guidewire. Even with the best of equipment, it can be technically challenging, or even impossible to access the common carotid artery in order to stent a stenosis at that location when using any existing carotid sheath that has a uniform flexibility along its entire length. If stenting is not possible, then the more invasive and potentially life threatening procedure of a surgical endarterectomy may be required. Therefore, there is an important need for an improved carotid sheath that allows for more successful guidance through the tortuous vascular anatomy that is encountered when attempting to stent a stenosis in a carotid artery.
Another problem with current approach for carotid stenting is that it requires the placement of a relatively large sheath (typically 8 French) or a thick walled 7 French carotid sheath system to deliver the relatively high profile carotid stent delivery catheter. The use of these larger diameter sheaths can lead to an increased likelihood of vascular access bleeding after the sheath has been removed. In general, there is a relationship between the outer diameter of the inserted sheath and the risk of bleeding complications. Thus, sheaths with thinner walls would have a smaller outside diameter. This would decrease the size of the hole at the vascular entry site which would reduce the risk of serious bleeding complications.